Om Ganpati Ganraj Gajanana

Among so many other stories about Lord Ganesha's birth, this one is the most popular. According to this, one day when Parvati went to take a bath, she asked Nandi to guard the door and not let anyone inside. But being Lord Shiva's faithful, when Shiva came, he didn't stop him from entering. Seeing that she didn't have anyone as faithful to her as Nandi was to Shiva, she collected the turmeric paste she used to clean her body with, and moulded it into Ganesha!